The aim of this application is to test novel E1 -deleted adenoviral recombinants expressing antigens of HIV-l for induction of mucosal and systemic transgene product-specific CD8+ T cell responses upon application to the oral cavity. Our long-term goal is to develop an optimized oral vaccination protocol in a pre-clinical mouse model for eventual use in a non-human primate model and then in humans. We will use the E1-deleted adenoviral (Ad) recombinant of the recently vectored simian serotype 6 (AdC6) either alone or in a heterologous prime boost regimen with the AdC68 recombinant which is also of simian origin or the well characterized Ad vector of the human serotype 5 (AdHu5). For the initial proof of principle studies we will use vectors expressing a truncated form of gag of HIV-l clade B. Results will then be extended to vectors expressing a codon-humanized polypeptide of gag/pol/nef in conjunction with vectors expressing a codon-humanized envelope protein (env) of HIV-1 clade B. In aim 1 we will determine the frequencies of transgene product-specific interferon (IFN)-gamma producing CD8+ T ceils that are induced in local and distant lymphoid tissue upon a single oral immunization with an Ad vector. Frequencies in different tissues will be determined during the effector and memory phase of the immune response. In aim 2, we will test for the induction of CD8+ T cell responses following oral prime boost regimens with homologous or heterologous Ad vaccine carriers. In aim 3, we will compare biological functions of CD8+ T cells induced by oral immunization to those induced by systemic vaccination emphasizing their lytic activity, cytokine production profile and epitope recognition repertoire. In aim 4, we will determine the tropism of the simian and human Ad recombinants upon oral application emphasizing localization of and cytokine production by transduced antigen presenting cells (APCs).